The lapidary collection of the Museum of Saint Sophia constitutes a priceless patrimony of sculpted marbles; though little known, it deserves of complete and systematic study. This guidebook is conceived as a useful companion devoted to the scientific divulgation of this important collection of sculptures of the city of Istanbul. Each marble sculpture, pleasantly arranged in the blooming garden in front of Saint Sophia, represents a significant "tessera" in the mosaic of the Late Antique and Byzantine city. This book offers all visitors to the Museum the opportunity to become more acquainted with these "marble treasures", treasures so frequently disregarded as a result of the overshadowing magnificence of the Justinianic building.